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Roles of transport and chemistry processes in global ozone change on interannual and multidecadal time scales
Author(s) -
Sekiya T.,
Sudo K.
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd020838
Subject(s) - troposphere , stratosphere , tropospheric ozone , atmospheric sciences , ozone , climatology , environmental science , middle latitudes , quasi biennial oscillation , atmospheric chemistry , microwave limb sounder , ozone layer , geology , meteorology , geography
This study investigates ozone changes and the individual impacts of transport and chemistry on those changes. We specifically examine (1) variation related to El Niño Southern Oscillation, which is a dominant mode of interannual variation of tropospheric ozone, and (2) long‐term change between the 2000s and 2100s. During El Niño, the simulated ozone shows an increase (1 ppbv/K) over Indonesia, a decrease (2–10 ppbv/K) over the eastern Pacific in the tropical troposphere, and an increase (50 ppbv/K) over the eastern Pacific in the midlatitude lower stratosphere. These variations fundamentally agree with those observed by Microwave Limb Sounder/Tropospheric Emission Spectrometer instruments. The model demonstrates that tropospheric chemistry has a strong impact on the variation over the eastern Pacific in the tropical lower troposphere and that transport dominates the variation in the midlatitude lower stratosphere. Between the 2000s and 2100s, the model predicts an increase in the global burden of stratospheric ozone (0.24 % /decade) and a decrease in the global burden of tropospheric ozone (0.82 % /decade). The increase in the stratospheric burden is controlled by stratospheric chemistry. Tropospheric chemistry reduces the tropospheric burden by 1.07 % /decade. However, transport (i.e., stratosphere‐troposphere exchange and tropospheric circulation) causes an increase in the burden (0.25 % /decade). Additionally, we test the sensitivity of ozone changes to increased horizontal resolution of the representation of atmospheric circulation and advection apart from any aspects of the nonlinearity of chemistry sensitivity to horizontal resolution. No marked difference is found in medium‐resolution or high‐resolution simulations, suggesting that the increased horizontal resolution of transport has a minor impact.